Pumps for liquids



Aug. 9, 1960 Filed May 22, 1957 P. w. CARVER 2,948,221

PUMPS FOR LIQUIDS 2 Sheets-Sheet 1 FIG].

AttorneyS Aug. 9, 1960 P. w. CARVER 2,948,221

PUMPS FOR LIQUIDS Filed May 22. 1957 2 Sheets-Sheet 2 Inventor by MAtforneyS United States Patent Office Patented Aug. 9, 1,960

PUlVIPS FOR LIQUIDS Philip Walker Carver, Nuthall, Nottingham; England,assignor to Kontak Manufacturing *Co. Ltd., Grantham,

Lincolnshire, England, a British company This invention relates to pumpsof the diaphragm type in which the fluid to be pumped is'separated froma motive fluid by the diaphragm which is pulsated by alternate pressureand suction of the motive fluidsupplied by a suitable pump and valvesystem. Such pumps are used for metering liquids for which purpose thevolume per stroke is readily adjustable. V I

According to this invention there is provided apump comprising adiaphragm in a chamber'the entire volume of which it sweeps on eachdelivery and'suction stroke, a one-way valve through which liquid isdrawn into the pump chamber on the suction stroke, and another-onephragmto cause the diaphragm to reciprocate in its chamber and an electricmotor driving therotating valve. Preferably means are provided foradjusting the pump delivery by adjusting the limit "of permissibletravel of the diaphragm on the suction stroke.

The pressure and suction sources may be created by a' Preferably .bothsuction port and delivery port are above the moving element of the pumpand communicate with them by passageways which are in part vertical, andon extensions of which are the said two valve controlled communicationsto the reservoir.

An example of this invention is illustratedin the accompanying drawingsof which Figure 1 is a vertical sec tion througha diaphragm pump andchangeover valves and Figure 2 is a like section through a rotary pumpwhich provides the pressure and suction. sources and the associateddeaerating device.

A pressure source and a suction source are created by a gear pump 110andxare connected to a valve body indicated generally by the figure 10,the pressure source by a pipe 11 and .the suction source by a pipe 12.

In the valve chamber 10 are two barrel plug valves 13 and 14 which aredriven in unison via a geared electric motor 15 so that pipes 16 and17'which lead out of the valve body are placed alternately incommunication with the pressure .side 18 and suction side 19 of thevalve chamber. Pipes 16 and 17 communicate with the pump indicatedgenerally at 20.

In this pump are two identical pump chambers 21 and 22 across whichextend pump diaphragms 23 and 24. Movement inwards of either diaphragms,i.e. toward the centre of the pump chamber draws in liquid from pipe 25through spring loaded valves 26 or 27 as'the case may beand movementoutwards expels liquid into pipe 28 through spring loaded valve 29 or 30as the case may be. Outward movement of the pump diaphragms is limitedby end plates 31, 32 which have holes through them 33 and 34 and inwardmovement is limited by diaphragm members 35 and 36. These diaphragmmembers 35 and 36 consist'of resilient material peripherally securedalong with pumping diaphragms, as shown, and supported by backingvplates 37 which constrain the diaphragm but rotary pump such as a gearor vane pump, with deaera:

tion, induction and relief arrangements providing a supply of liquid onwhichthe pump may expend' energy, thus creating the suction and pressuresources; 1 j

The movement of the pump diaphragm may be limited by a support diaphragmwhich latter forms one wall of the pump chamber against which the pumpdiaphragm moves on the suction stroke and which is "displaceable toadjust or vary the extent of the diaphragm stroke;

permit it to move from one purely frusto-conical position to another aslater described. 4

Pressure and suction communicated to the pump chambers by pipes 16 and17 is communicated to chambers 38 and 39 on the inner side of the twodiaphragms 35 The pump may comprise a pairof pump diaphragms in chambersconnected to a valve body in which two valves are provided driven by thesaid motor'to connect alternately the sources of pressure and suction toeach pump diaphragm.

In this case the stroke limiting supportldiaphra'gm may be spring loadedback on to a common stop which may be of tapered form and adjustable toforce them apart or allow them to come together thus. altering'in unisonthedelivery of the two pump chambers. More than one diaphragm pump unitmay be driven from one actuating pump.

The deaerating arrangement may be provided by a reserve tank above thepump chamber which is not normally completely filled with liquid so thatthere is an air space above the liquid, a communication being providedfrom the reservoir to the suction side of the pump such communicationbeing through a port opened and closed by a float in a chamber below thereservoir, the said port being above the suction port, anothercommunication being provided through a loaded valve from the deliveryside of the pump to the reservoir, the valve being situated above thedelivery port.

Preferably a second connection is provided between the reservoir and thesuction side of the pump through a loaded valve situated above thesuction port.

and 36 and thence by holes 40 through the diaphragms to thediaphragms 23and 24 and by these means the said diaphragms are caused to movealternately outward or inward thus sweeping the entire volume ofchambers 21 and 22.

It will also be appreciated that while diaphragm 23 is on its suctionstrokediaphragm 24 is on the delivery stroke and vice versa. The rigidcentral disc portions 41and42 of the diaphragms 35 and 36 carry spindles43 and 44 the ends of which are' held by springs 45 and 46 against atapered member 47 carried by a threaded spindle 48'threaded into aflange 49 on the pump body phragms apart or raised to bring themtogether thus controlling the volume of the pump chambers.

A knurled head 50 may carry a scale which can be used to calibrate thepump delivery.

7 Turning. now to Figure 2 the gear pump driven by an electric motor 111is'mounted in a pump chamber 112. The pumpcauses a continual suction inpipe 12 which communicates with the pump via a vertical conduit 114 anda continuous pressure in pipe 11 which communicates with the pumpthrough a vertical conduit 115.

Situated above the pump chamber is a reservoir 117 filled with liquidthe level of which is indicated at 118, thus providing an air space 119above it which is vented by means not shown to the atmosphere.

Liquid can pass into the reservoir from pipe through spring loaded valve120 and from the reservoir into vertical conduit 114 through springloaded valve 121.

A further communication is provided between the conduit 114 and thereservoir chamber through a port 122 opened and closed by a valveelement 123 carried by a float 124 floating in a chamber 125 whichcommunicates through port 126 with the lower side of valve 121.

Air bubbles in the suction side of the pump will find their way to thefloat chamber 125 causing the level of the liquid in the chamber tofall, the float therefore to fall, opening the port 122 through whichthe bubbles will escape into the reservoir and oil will replenish thefloat chamber 125. Bubbles on the delivery side of the pump will passinto conduit 115 collecting under valve 120 which lies on the top of anextension 115a of conduit 115 above the pipe 11.

The system is so arranged that the valves 121 and 126 will open only ona greater suction or delivery pressure than that required to draw inliquid through valves 26 and 27 and pump it out through valves 29 and 30against the head against which the diaphragm pump is delivering, but thedisplacement volume of the pump 110 is such that valves 121 and 120 willbe continuously open and there will be a constant circulation throughthe reservoir 117 so that any bubbles will reach the reservoir throughvalve 120. The pump 110 is so arranged in relation to the diaphragm pumpthat thereis a fall between pump 110 and the diaphragm chamber to helpto circulate bubbles in the system. A fall of 1 inch per foot has beenfound satisfactory.

I claim:

1. A metering pump for delivering a measured quantity of liquid per unitof time comprising in combination, a housing having a compartment, aflexible diaphragm dividing said compartment into two chambers, theentire volumes of which it sweeps on each delivery and suction stroke, aone-way inlet valve and a one-way discharge valve connected to one ofsaid chambers for handling the per-stroke measured quantity of pumpedliquid, sources of continuous suction and pressure, valve means arrangedto alternately connect said sources to the other of said chambers tocause the diaphragm to reciprocate in its compartment and meansindependent of the suction and pressure sources to actuate said valvemeans at a fixed speed. I

2. The metering pump as claimed in claim 1 in which said compartment hasopposed walls each of substantially frusto-conical shape, the one of.said walls up to which the diaphragm moves on one stroke being flexible,means to move said last mentioned wall to vary the volume of thecompartment swept by the diaphragm, said means substantially maintainingthe frusto-conical shape of the wall whereby the diaphragm at one end ofits stroke will rest against said wall with minor edge flexing.

3. A metering pump as claimed in claim 1 embodying two complete pumps asdescribed and said valve means being arranged to connect the sources ofsuction and pressure alternately to one side of each diaphragm so thatone is on its delivery stroke while the other is on its suction strokeand vice versa to effect substantially continuous delivery.

4. A metering pump embodying two complete pumps as claimed in claim 2,said valve means being arranged to connect the sources of suction andpressure alternately '4 to one side of each diaphragm so that one is onits delivery stroke while the other is on its suction stroke and viceversa, the two pumps being so disposed that the movable walls areadjacent each other, spring means urging said walls toward each otherand single means to force the said walls apart to adjust delivery rate.

5. A metering pump as claimed in claim 4 in which the said valve meansare two rotating valves each having a delivery side and an inlet side,means connecting the delivery side of each valve respectively to theadjustable wall side of a different one of said chambers, and means toalternately and oppositely connect the inlet sides of said valves to thesaid sources of suction and pressure.

6. A metering pump as claimed in claim 1 in which the sources ofpressure and suction comprise a rotary pump system having a motor drivenrotary pump of greater displacement volume than necessary to cause thesaid pump diaphragm to sweep both its chambers, a liquid reservoir forsaid rotary pump, a loaded valve connecting the pressure side of saidrotary pump to the reservoir and a loaded valve connecting the reservoirto the suction side of the rotary pump whereby the excess displacementcauses a flow through the loaded valves into and out of the reservoir.

7. A metering pump as defined in claim 6 including means co-operatingwith the reservoir and the suction side of the rotary pump to deaeratethe liquid in the rotary pump system.

I 8. A- metering pump as defined in claim 7 in which the deaeratingmeans includes the reservoir open to atmosphere and incompletely filled,an auxiliary passage between the reservoir and the suction side of thepump around said loaded valve which connects the suction side of thepump to the reservoir and including a port and a float chamber below thereservoir, a valve actuated by saidfioat to close or open the port tothe reservoir, said port being above the connection between the suctionside of the rotary pump and the diaphragm pump chamber.

9'. The metering pump as claimed in claim 8 in which the connectionsbetween the rotary pump inlet and outlet and the reservoir lie above theconnections between said rotary pump inlet and outlet and the diaphragmpump chamber. 7

10. The metering pump as claimed in claim 9 in which the connectionsfrom the suction and delivery sides of the rotary pump to the diaphragmpump chamber are located vertically abovethe rotary pump, at least apart of each connection being vertical, extensions of said verticalparts leading to said loaded valves between the rotary pump andreservoir.

References Cited in the file of this patent UNITED STATES PATENTS

